What was the real purpose of the three types of reforms the Holy
Quran makes?

The whole purpose of the Quran is the three reforms, and all its
teachings are directed towards that end. All other directions are
the means for the achievement of those reforms.

First, God desires to teach man the rules of social behaviour like
sitting, standing, eating, drinking, talking etc., and thus to
deliver him from a state of barbarism and distinguish him from the
animals and thus bestow upon him an elementary moral state which
might be described as social culture. He then desires to regulate
his elementary moral habits so that they should acquire the
character of high moral qualities. Both of these methods are part
of the same process as they are related to the reform of man's
natural condition. There is between them a difference only of
degree. The All-Wise One has so arranged the moral system that man
should be able to rise from a low to a high moral condition.

The Holy Quran claims to be more complete and more perfect than all
other books of guidance, inasmuch as the other books had not the
opportunity of carrying out the three types of reforms which the
Holy Quran was designed to carry out. The purpose of the Holy Quran
was to elevate savages into men, and then to equip them with moral
qualities, and finally raise them to the level of godly persons.
The Holy Quran thus comprehends all those three projects.